Various questions about Smart 451, tyres, rims, etc.

Hello together, I recently own a Smart Brabus Cabrio (built in 2009) and have the following rims on it: 175/50 R16 77T (front) 225/35 R17 82T (intens) I used the search function and there was the following combination proposed by two users: 175/55 R15 195/50 R15 The three questions I ask myself: 1.) They fit on my Smart? 2.) Which rims do I use for it? The Brabus rims don’t fit for it? (please ask for help with the purchase of rims from small ads or eBay) 3.) Which tyres? I looked at mature low price and there is a lot of choice.